Tools attached to a robot are consumed or worn by different using modes. For example, in the case of a spot welding robot, a welding gun is used as a tool, but the gun tip is consumed in accordance with the number of robot's works. In this case, a position of a TCP (Tool Center Point) is changed by the consumption of the tip, so that the robot is required to correct the changed position to perform the welding operation. For this reason, a spring mechanism for correcting the change is ordinarily located in a mechanical section of the welding gun.
Further, for example, in the case of a grinding robot, a grinder is used as a tool, but the grinder attached to the robot is worn in accordance with the working time when grinding the workpiece surface. In this case, there is also a need of correcting the changed position of the TCP, for this reason, a spring mechanism for pressing the grinder against the workpiece must be attached to the grinder likewise.
However, the spring mechanisms as mentioned above causes problems such as of making the welding gun or grinder heavy and the cost higher. In addition, in the case of the grinding robot, there is a limit of pressing force by the spring mechanism, so that the grinder must be exchanged when exceeding the limit. This increases the frequency of the grinder change.
Furthermore, in the case of the grinding robot, in order to allow the robot to perform suitable grinding operations in accordance with the consumption of the grinder, it is required to prepare a plurality of robot manipulation programs in addition to the spring mechanism. For this reason, it is troublesome and difficult to handle and control the robot manipulation programs.